scholarly journals Scratch Behaviour of Bulk Silicon Nitride Ceramics

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 707
Author(s):  
Xiaolan Xiao ◽  
Jiayun Deng ◽  
Qiang Xiong ◽  
Qiusheng Yan ◽  
Zhengtao Wu ◽  
...  
Keyword(s):  
Brittle Fracture ◽  
Material Removal ◽  
Normal Load ◽  
Polished Surface ◽  
Si3n4 Ceramic ◽  
Abrasive Particles ◽  
Nitride Ceramics ◽  
Indentation Tests ◽  
Three Stages ◽  
Penetration Depths

Si3N4 ceramic is generally recognized as being difficult to machine due to its hardness and brittleness. It is necessary to control the normal load applied and the machined depth of the abrasive particles in order to eliminate surface/subsurface damage and defects during the grinding or polishing. In this study, scratch experiments were conducted on the polished surface of Si3N4 specimens to investigate the brittle–ductile transformation and the evolution of material removal mechanisms. In addition, the cracking behaviour of Si3N4 ceramic was characterized by indentation tests. The Vickers indentation produced cracks that exhibited good developmental integrity and geometric symmetry. The results indicate that the scratch track can be divided into three stages: the ductile regime, the brittle–ductile coexisting stage, and the brittle fracture regime. The critical loads and the corresponding penetration depths of cracking occurrence in Si3N4 were recorded. The material removal of Si3N4 ceramic was primary attributed to ductile regime removal when the load was less than 9.8 N. Microcrack initiation on the subsurface was observed when the penetration depth of the scratch tip reached 8 μm or the depth of the indentation tip reached 3.2 μm. Microcracks expanded rapidly as the load was further increased, resulting in a brittle fracture of the Si3N4 ceramic.

Development of a New Plate Polishing Technique with an Instantaneous Tiny-Grinding Wheel Cluster Based on Magnetorheological Effect

2008 ◽  
Vol 53-54 ◽  
pp. 155-160 ◽  
Author(s):  
Qiu Sheng Yan ◽  
Ai Jun Tang ◽  
Jia Bin Lu ◽  
Wei Qiang Gao
Keyword(s):  
Surface Roughness ◽  
Material Removal Rate ◽  
Material Removal ◽  
Removal Rate ◽  
Grinding Wheel ◽  
Abrasive Particles ◽  
Magnetorheological Effect ◽  
Material Removal Model ◽  
Mr Effect ◽  
Removal Model

A new plate polishing technique with an instantaneous tiny-grinding wheel cluster based on the magnetorheological (MR) effect is presented in this paper, and some experiments were conducted to prove its effectiveness and applicability. Under certain experimental condition, the material removal rate was improved by a factor of 20.84% as compared with the conventional polishing methods with dissociative abrasive particles, while the surface roughness of the workpiece was not obviously increased. Furthermore, the composite of the MR fluid was optimized to obtain the best polishing performance. On the basis of the experimental results, the material removal model of the new plate polishing technique was presented.

Non-Contact Ultrasonic Abrasive Machining of Wire-Electrical Discharge Machined SUS304 Steel

2017 ◽  
Author(s):  
K. L. Tan ◽  
S. H. Yeo
Keyword(s):  
Material Removal ◽  
Cavitation Erosion ◽  
Removal Rate ◽  
Recast Layer ◽  
Ultrasonic Machining ◽  
Abrasive Machining ◽  
Efficient Removal ◽  
Abrasive Particles ◽  
The Poor ◽  
Lower Material

Non-contact ultrasonic abrasive machining (NUAM) is a variant of ultrasonic machining (USM). In NUAM, material is removed predominantly by cavitation erosion in abrasive slurry. Due to a significantly lower material removal rate than traditional USM, NUAM is investigated for its applicability on surface modification and finishing in this study. Experiments were conducted on SUS304 steel samples machined by wire electrical discharged machining (WEDM). Due to the thermal spark phenomenon during WEDM, a thermal recast layer, of thickness approximately 15 μm, is often left over on the specimen’s surface after the process. The undesired thermal recast layer contributes to the poor surface integrity of specimens. A NUAM system was configured using a 40 kHz ultrasonic system. Ultrasonic vibration amplitude of 70 μm at the horn tip was used to generate cavitation bubbles in the abrasive slurry. NUAM was found to be effective in removing the unstable thermal recast layers by means of cavitation erosion. As a result, the average surface roughness, Ra, of the specimens improved from approximately 2.5 μm to ∼1.7 μm after 20 minutes of processing time. Furthermore, the addition of abrasive particles was observed to aid in more efficient removal of thermal recast layers than a pure cavitation condition.

Material Removal and Application by Chemical Impact Reaction in Nano-Abrasive Jet Polishing

2013 ◽  
Vol 631-632 ◽  
pp. 550-555
Author(s):  
Wen Qiang Peng ◽  
Sheng Yi Li ◽  
Chao Liang Guan ◽  
Xin Min Shen
Keyword(s):  
Material Removal ◽  
Abrasive Particle ◽  
Precision Machining ◽  
Optical Surface ◽  
Polishing Process ◽  
Abrasive Particles ◽  
Mechanical Process ◽  
Abrasive Jet Polishing ◽  
Ultra Precision ◽  
Machining Properties

Material removed by mechanical process inevitably causes surface or subsurface damage containing cracks, plastic scratch, residual stress or dislocations. In nano-abrasive jet polishing (NAJP) the material is removed by chemical impact reaction. The chemical impact reaction is validated by contrast experiment with traditional lap polishing process in which the material is mainly removed through mechanical process. Experiment results show the dependence of the abrasive particles on the choice of materials. Even if the abrasive particle and the workpiece are composed of similar components, the machining properties are remarkably different due to slight differences in their physical properties or crystallography etc. Plastic scratches on the sample which was polished by the traditional mechanical process are completely removed by NAJP process, and the surface root-square-mean roughness has decreased from 1.403nm to 0.611nm. The NAJP process will become a promising method for ultra precision machining method for ultrasmooth optical surface.

Development of the improved Preston equation for abrasive flow machining of aerofoil structures and components

2018 ◽  
Vol 233 (9) ◽  
pp. 1397-1404 ◽  
Author(s):  
Kai Cheng ◽  
Yizhi Shao ◽  
Mitul Jadva ◽  
Rodrigo Bodenhorst
Keyword(s):  
Surface Roughness ◽  
Material Removal ◽  
Machining Process ◽  
Dynamics Simulation ◽  
Abrasive Machining ◽  
Abrasive Particles ◽  
Abrasive Flow Machining ◽  
Flow Features ◽  
The Media ◽  
Experimental Trials

The paper presents an improved Preston equation, which aims to be part of the industrial application to abrasive flow machining. The equation will aid the engineers to optimise the process for desired surface roughness and edge tolerance characteristics on complex geometries in an intuitive and scientific manner. The methodology presented to derive the equation underpins the fundamental cutting mechanics of abrasive machining or polishing assuming all abrasive particles within the media are spherical as manufacturers defined. Further to derivation, full four factorial experimental trials and computational fluid dynamics simulation are implemented to generate the flow features of media on coupon to evaluate and validate the equation for its competency and accuracy on prediction of material removal. The modified Preston equation can significantly contribute to optimise the abrasive flow machining process, and will advantage the integrated machine design to predict better virtual surface roughness and material removal rates.

Parametric Optimization of Magnetic Abrasive Finishing Using Adhesive Magnetic Abrasive Particles

2019 ◽  
Vol 7 (2) ◽  
pp. 34-47
Author(s):  
Palwinder Singh ◽  
Lakhvir Singh ◽  
Arishu Kaushik
Keyword(s):  
Surface Finish ◽  
Medical Equipment ◽  
Material Removal ◽  
Parametric Optimization ◽  
Removal Rate ◽  
Improvement Rate ◽  
Magnetic Abrasive Finishing ◽  
Abrasive Particles ◽  
Abrasive Finishing ◽  
Depth Analysis

A very precise surface finish is desirable in manufacturing semiconductors, medical equipment, and aerospace parts. The examinations on magnetic abrasive finishing (MAF) processes are being done for the modern industry. This newly developed process is serving the industry to achieve the desired level of precision and surface finish. This research represents the MAF of aluminum pipes using adhesive magnetic abrasive particles. The different process parameters were optimized using the Response Surface Methodology (RSM) method to gain an in-depth analysis of surface roughness in terms of roughness improvement rate (RIR), and material removal rate (MRR). The achieved maximum RIR and MRR was 81.49% and 2.74mg/min, respectively. The finished workpieces were microscopically investigated by scanning electron microscopy (SEM) to further study the mechanism of MAF process.

Studying the Temperature Effect During the High-Pressure Phase Transformation of Silicon via Indentations

2012 ◽  
Author(s):  
Deepak Ravindra ◽  
John Patten ◽  
Muralidhar K. Ghantasala
Keyword(s):  
High Pressure ◽  
Phase Transformation ◽  
Temperature Effect ◽  
Brittle Material ◽  
Material Removal ◽  
Thermal Softening ◽  
High Pressure Phase ◽  
Ductile Mode ◽  
Indentation Tests ◽  
Pressure Phase

Micro-laser assisted machining (μ-LAM) is a novel micro/nano machining technique developed for ductile mode machining of ceramics and semiconductors. Ductile mode material removal is possible in a nominally brittle material due to the high-pressure phase transformation (HPPT) phenomenon during the machining process. This study isolates the pressure and temperature effect in the μ-LAM process. The μ-LAM process is unique whereby the pressure and temperature effect occur concurrently leading to the material removal process. The effect of temperature and thermal softening is studied via indentation tests using a cutting tool. In the precisely controlled indentation tests, laser heating is applied at various stages to determine the phase (i.e. atmospheric Si-I phase or high pressure phases that benefits most from the thermal softening effect. The indentation depths are measured and compared for each condition to identify the enhanced ductility of the nominally brittle material caused by the laser irradiation.

Progress in Silicon Nitride Ceramics in Japan

1992 ◽  
Vol 287 ◽  
Author(s):  
K. Komeya
Keyword(s):  
Silicon Nitride ◽  
Cost Reduction ◽  
Industrial Applications ◽  
Powder Synthesis ◽  
Materials Development ◽  
Nitride Ceramics ◽  
Government Project ◽  
Three Stages ◽  
The Government ◽  
Fine Ceramics

ABSTRACTProgress in silicon nitride ceramics in Japan is reviewed. It is historically divided into three stages. Through these stages, basic experimental research and innovations have progressed along with industrial applications, and the government project on fine ceramics in 1981-1992 has contributed much to the acceleration in the development of silicon nitride ceramics. Focus in this paper is mainly on materials development including raw powder synthesis and exploration for applications. The future prospect of utilizing silicon nitride as an engineering material, however, is seen to depend on cost reduction and reliability improvement.

scholarly journals Theoretical Study of Path Adaptability Based on Surface Form Error Distribution in Fluid Jet Polishing

2018 ◽  
Vol 8 (10) ◽  
pp. 1814 ◽  
Author(s):  
Yanjun Han ◽  
Lei Zhang ◽  
Cheng Fan ◽  
Wule Zhu ◽  
Anthony Beaucamp
Keyword(s):  
Material Removal ◽  
Bulk Material ◽  
Critical Evaluation ◽  
Error Distribution ◽  
Residual Error ◽  
Polished Surface ◽  
Surface Form ◽  
Optimization Strategy ◽  
Form Error ◽  
The Difference

In the technology of computer-controlled optical surfacing (CCOS), the convergence of surface form error has a close relationship with the distribution of surface form error, the calculation of dwell time, tool influence function (TIF) and path planning. The distribution of surface form error directly reflects the difference in bulk material removal depth across a to-be-polished surface in subsequent corrective polishing. In this paper, the effect of path spacing and bulk material removal depth on the residual error have been deeply investigated based on basic simulation experiments excluding the interference factors in the actual polishing process. With the relationship among the critical evaluation parameters of the residual error (root-mean-square (RMS) and peak-to-valley (PV)), the path spacing and bulk material removal depth are mathematically characterized by the proposed RMS and PV maps, respectively. Moreover, a variable pitch path self-planning strategy based on the distribution of surface form error is proposed to optimize the residual error distribution. In the proposed strategy, the influence of different bulk material removal depths caused by the distribution of surface form error on residual error is compensated by fine adjustment of the path spacing according to the obtained path spacing optimization models. The simulated experimental results demonstrate that the residual error optimization strategy proposed in this paper can significantly optimize the overall residual error distribution without compromising the convergence speed. The optimized residual error distribution obtained in sub-regions of the polished surface is more uniform than that without optimization and is almost unaffected by the distribution of parent surface form error.

scholarly journals Slicing Ceramics on Material Removed by a Single Abrasive Particle

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4324
Author(s):  
Yao-Yang Tsai ◽  
Ming-Chang Wu ◽  
Yunn-Shiuan Liao ◽  
Chung-Chen Tsao ◽  
Chun-Yao Hsu
Keyword(s):  
Mathematical Model ◽  
Plastic Deformation ◽  
Brittle Fracture ◽  
Material Removal ◽  
Equations Of Motion ◽  
Abrasive Particle ◽  
Brittle Materials ◽  
Machining Parameters ◽  
Wire Saw ◽  
Cutting Model

Multi-wire saw machining (MWSM) used for slicing hard-brittle materials in the semiconductor and photovoltaic industries is an important and efficient material removal process that uses free abrasives. The cutting model of single-wire saw machining (SWSM) is the basis of MWSM. The material removal mechanism of SWSM is more easily understood than MWSM. A mathematical model (includes brittle fracture and plastic deformation) is presented in this paper for SWSM ceramic with abrasives. This paper determines the effect of various machining parameters on the removal of hard-brittle materials. For brittle fracture of SWSM ceramics, the minimum strain energy density is used as a fracture criterion. For plastic deformation of SWSM ceramics, the material removal is calculated using equations of motion. Actual wire-sawing experiments are conducted to verify the results of the developed mathematical model. The theoretical results agree with experimental data and practical experience. From the developed mathematical model, brittle fracture plays a major role in material removal of SWSM ceramics. Wire speed (S) and working load (P) are positively correlated with material removal of SWSM ceramics. The coefficient of friction is low, a lateral crack, which propagates almost parallel to the working surface, leads to more brittle fracture and material removal is increased.

Brittle Fracture Generated by Abrasion Wear in Borided Low Carbon Steel

2005 ◽  
Author(s):  
Marti´n Castillo ◽  
Manuel Vite ◽  
L. H. Herna´ndez ◽  
G. Villa ◽  
G. Urriolagoitia
Keyword(s):  
Carbon Steel ◽  
Brittle Fracture ◽  
Low Carbon Steel ◽  
Particle Morphology ◽  
Principal Characteristic ◽  
Low Carbon ◽  
Abrasive Particles ◽  
Hard Particles ◽  
Abrasion Wear ◽  
Steel Aisi

This work is related to failure as a consequence of brittle fracture by abrasion wear. The experimental evidence showed that this situation depends on the size and shape of the abrasive particles and their velocity when they are interacting against the abraded surface. The particle morphology determines the type of failure, in which the crack may propagate. This can be in a lateral and radial direction. Also this situation is observed in low carbon steel (AISI 8620) which has been borided previously. In accordance with the results, the strength is improved by: developing phases, varying thickness of the borided layer and increasing the hardness. At the same time, a hardness analysis of the borided steel and the abrasive surfaces was carried out. The hardness is the principal characteristic which increases the abrasion resistance and the borided improved resistant to wear. However, it has different behaviour according to the type mechanism of abrasion wear (two or three bodies). In the case of three bodies, it is necessary to take into account the superficial characteristic, because over rough surfaces, the hard particles deteriorate the surface of the specimen. On the other hand, on smooth borided surfaces, generally the particles slip without several damage.

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